From 4ed70a930202b103e7e80b8dc925e0aaa4622595 Mon Sep 17 00:00:00 2001
From: Martin Sustrik <sustrik@fastmq.commkdir>
Date: Wed, 29 Jul 2009 12:07:54 +0200
Subject: initial commit

---
 src/load_balancer.cpp | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 src/load_balancer.cpp

(limited to 'src/load_balancer.cpp')

diff --git a/src/load_balancer.cpp b/src/load_balancer.cpp
new file mode 100644
index 0000000..63dc15c
--- /dev/null
+++ b/src/load_balancer.cpp
@@ -0,0 +1,130 @@
+/*
+    Copyright (c) 2007-2009 FastMQ Inc.
+
+    This file is part of 0MQ.
+
+    0MQ is free software; you can redistribute it and/or modify it under
+    the terms of the Lesser GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    0MQ is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    Lesser GNU General Public License for more details.
+
+    You should have received a copy of the Lesser GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "../include/zs.h"
+
+#include "load_balancer.hpp"
+#include "pipe_writer.hpp"
+#include "err.hpp"
+#include "session.hpp"
+#include "msg.hpp"
+
+zs::load_balancer_t::load_balancer_t () :
+    session (NULL),
+    current (0)
+{
+}
+
+void zs::load_balancer_t::set_session (session_t *session_)
+{
+    zs_assert (!session);
+    session = session_;
+}
+
+void zs::load_balancer_t::shutdown ()
+{
+    //  No need to deallocate pipes here. They'll be deallocated during the
+    //  shutdown of the dispatcher.
+    delete this;
+}
+
+void zs::load_balancer_t::terminate ()
+{
+    //  Pipe unregisters itself during the call to terminate, so the pipes
+    //  list shinks by one in each iteration.
+    while (!pipes.empty ())
+        pipes [0]->terminate ();
+
+   delete this;
+}
+
+zs::load_balancer_t::~load_balancer_t ()
+{
+}
+
+void zs::load_balancer_t::attach_pipe (pipe_writer_t *pipe_)
+{
+    //  Associate demux with a new pipe.
+    pipe_->set_demux (this);
+    pipe_->set_index (pipes.size ());
+    pipes.push_back (pipe_);
+}
+
+void zs::load_balancer_t::detach_pipe (pipe_writer_t *pipe_)
+{
+    //  Release the reference to the pipe.
+    int index = pipe_->get_index ();
+    pipe_->set_index (-1);
+    pipes [index] = pipes.back ();
+    pipes [index]->set_index (index);
+    pipes.pop_back ();
+}
+
+bool zs::load_balancer_t::empty ()
+{
+    return pipes.empty ();
+}
+
+bool zs::load_balancer_t::send (zs_msg *msg_)
+{
+    //  If there are no pipes, message cannot be sent.
+    if (pipes.size () == 0)
+        return false;
+
+    //  Find the first pipe that is ready to accept the message.
+    bool found = false;
+    for (pipes_t::size_type i = 0; !found && i < pipes.size (); i++) {
+//        if (pipes [current]->check_write (msg))
+            found = true;
+//        else
+//            current = (current + 1) % pipes.size ();
+    }
+
+    //  Oops, no pipe is ready to accept the message.
+    if (!found)
+        return false;
+
+    //  Send the message to the selected pipe.
+    write_to_pipe (pipes [current], msg_);
+    current = (current + 1) % pipes.size ();
+
+    //  Detach the original message from the data buffer.
+    zs_msg_init (msg_);
+
+    return true;
+}
+
+void zs::load_balancer_t::flush ()
+{
+    //  Flush all pipes. If there's large number of pipes, it can be pretty
+    //  inefficient (especially if there's new message only in a single pipe).
+    //  Can it be improved?
+    for (pipes_t::iterator it = pipes.begin (); it != pipes.end (); it ++)
+        (*it)->flush ();
+}
+
+void zs::load_balancer_t::write_to_pipe (class pipe_writer_t *pipe_,
+    struct zs_msg *msg_)
+{
+    if (!pipe_->write (msg_)) {
+        //  TODO: Push gap notification to the pipe.
+        zs_assert (false);
+    }
+}
+
-- 
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